The present invention relates generally to chucks and is more particularly concerned with a new and improved chuck of the indexing type.
Indexing chucks are employed where it is desired to incrementally pivot a piece of work without releasing it from the chuck so that multiple operations such as machining operations may be performed thereon. These chucks conventionally include a pair of radially movable jaws for gripping the work and for rotating the work about the jaw axis through predetermined angles to present new faces or sides of the work to the machine tool operating thereon. Usually the chuck employs a pair of diametrically opposed gripping jaws that are each movable inwardly so as to grasp the workpiece under full jaw pressure yet are capable of being rotatably indexed and secured within each indexed position so as to present the appropriate surface of the workpiece to the machine tool. As will be appreciated, it is imperative that the workpiece be firmly and securely held by the chuck in each of its rotatably indexed positions.
Accordingly, a principle object of the present invention is to provide a chuck of the indexing type that insures maximum rigidity when the jaws close on the workpiece yet at the same time provides balanced jaw pressure at each point of jaw contact with the workpiece regardless of the indexed orientation of the jaws.
Another object of the present invention is to provide a chuck of the type described that includes an improved jaw closing mechanism wherein the power for moving the jaw is centered directly behind the jaw as it is closed on the workpiece and provides an equalized jaw pressure thereon. Included in this object is the provision for a chuck having an index locking mechanism that promotes rigidity between the jaw housing and the workpiece through the locking portions of the opposing jaw members.
Still another object of the present invention is to provide a new and improved indexing chuck of the type described that provides support for the workpiece gripping jaws not only along the axis of the jaws that are generally perpendicular to the direction of machine tool pressure but also in a direction that is directly opposed to the direction of machine tool pressure.
A still further object of the present invention is to provide an indexing chuck of the type described that provides the features mentioned hereinbefore yet is constructed of economical standard components without sacrificing durability, precision or desired operating characteristics within the chuck.
A further object of the present invention is to provide a chuck of the indexing type that utilizes a housing having rigidly interconnected top and bottom plates with the opposed jaws being firmly secured between the plates for added rigidity and with the indexed locking and supporting mechanism mounted on the plates and providing a wedging action that rapidly locks and unlocks the master jaws for indexing and further promotes the rigidity of the chuck construction when the jaws are locked in their indexed positions.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.
These and related objects are accomplished in accordance with the present invention by providing a chuck of the indexing type comprising a chuck housing, a pair of opposed jaw supports mounted within the housing with one of the supports being fixedly secured thereto and the other of the supports including a cam surface and being movable toward and away from the fixed support. A jaw is mounted on each support for rotation relative thereto into any one of a number of indexed positions. A jaw operator mounted on the housing includes drive means engaging the cam surface of the movable support for driving the movable support and its associated jaw toward and away from the fixed support. Another feature of the invention is the provision for index locking means for each jaw mounted on the housing for locking the jaws against rotation. The rigidity of the chuck is enhanced by the chuck housing construction that includes a pair of substantially planar support plates rigidly interconnected in spaced parallel relationship with at least one of the plates having an enlarged central aperture of sufficient size to readily permit passage of a workpiece therethrough for engagement by the opposed jaws. One of the jaws of the chuck also may be provided with a plurality of fluid-operated work stabilizing clamps and a closed fluid circuit interconnecting the clamps for controlling engagement of the workpiece thereby.
A better understanding of the invention will be obtained from the following detailed description and the accompanying drawings which set forth an illustrative embodiment indicative of the way in which the principles of the invention are employed.